The present invention relates to clamping or securing devices in general, and more particularly to a mechanism configured to hold a working tool or device, such as a grinding wheel, to a rotatable drive spindle. In particular, the invention relates to a hand actuable clamping device having a feature to more effectively hand tighten the mechanism.
Hand tightened clamping devices are well known in the art. For example, U.S. Pat. Nos. 5,567,100 and 5,577,872 describe various embodiments of such tightening or clamping devices. These patents describe a tightening screw or clamping device having a torque enhancing feature. The device includes an operating ring that is hand actuated in order to screw the device onto a threaded spindle. U.S. Pat. No. 4,976,071 to Stabler describes a clamping device for portable grinding machines having a clamping nut that is screwed onto a threaded drive spindle to clamp a grinding disk in place. The device includes a clamping fork which is pivoted between a clamping position and a loosened position. The clamping fork is not used to manually rotate the device, but applies an axially directed pressing force when moved from its loosened position to the clamping position.
U.S. Pat. No. 5,494,368 to Matthews describes a clamping device or fastener that is also threaded onto a drive spindle. The fastener includes a gripping device for manual tightening or loosening. This gripping device is described as a single planar member pivotally connected to the fastener. The planar member is pivoted to an upright position wherein it can be manually grasped to apply a torque to the fastener.
The present invention provides alternative improved means for enhancing the hand tightening or loosening operations of conventional clamping or fastening nuts.